1. Field of the Invention
The present invention relates to a disk drive, and more particularly to a technique for preventing dew from forming on internal components of a hard disk drive.
2. Description of the Related Art
The moisture existing on the inside of a hard disk drive exerts a bad influence upon inside components. Especially dew formed in a state of saturation exerts bad effects upon an operation of components. Therefore, it is necessary to prevent dew from being formed inside when manufacturing a hard disk drive. There are normally two techniques to prevent dew from being formed on the inside of a hard disk drive. One technique is to seal the inside of a hard disk drive by using a gasket or a tape. The sealing material of the gasket or tape cutting off the inside of a hard disk drive from the outside has the property of preventing dew from penetrating thereinto, but the cost for preventing dew becomes expensive. Another technique is to use a breather filter. The breather filter is installed on the upper surface of a cover of a main body and it is widely used more than sealing. The breather filter is used for the following reasons.
By a high speed rotation of the hard disk, an air flow is generated on the inside of a hard disk drive and accordingly, a distribution of air pressure occurs. The pressure at the moment is lower than that of the outside of the hard disk drive and accordingly the contaminated outside air flows into the inside of the hard disk drive, resulting in contamination of the inside. An inlet opening is installed for air flow and is formed between the outside to the inside and the breather filter is installed in the opening for allowing clean air to flow in. The inlet opening equipped with a breather filter is used as a vent when the hard disk drive is not being operated. As the air passes out of or into the inside of the hard disk drive, the humidity of the inside is adjusted somewhat. Accordingly, the dew formed in a state of saturation is also somewhat prevented. It is understood that a response of an inside temperature according to an outside temperature is faster than that of an inside humidity according to an outside humidity.
When a hard disk drive using the breather filter is moved from a state of a high temperature and high humidity to a reversed state, dew is formed inside due to the temperature and humidity cycle. When a hard disk drive at a warehouse having a high temperature and humidity is moved to an office having a low temperature and low humidity, dew can be formed on the internal parts of the hard disk drive. The dew exerts bad effects upon inside components of the hard disk drive such as the head and the recording medium.
The following patents each disclose features in common with the present invention but do not teach or suggest a technique for preventing dew from forming on internal components of a hard disk drive utilizing a dew forming plate having a thermal conductivity greater than that of the cover of the hard disk drive as in the present invention.
U. S. Pat. No. 5,590,001 to Ino et al., entitled Breather Filter Unit For Magnetic Disk Drive, U.S. Pat. No. 5,417,743 to Dauber, entitled Self-Adhesive Vent Filter And Adsorbent Assembly With A Diffusion Tube, U. S. Pat. No. 5,293,286 to Hasegawa et al., entitled Magnetic Disk Apparatus For Maintaining An Optimum Humidity In A Head Disk Assembly, U.S. Pat. No. 5,075,807 to Inoue et al., entitled Magnetic Disk Device Including Humidity Controller In Disk Enclosure, U.S. Pat. No. 5,229,899 to Brown et al., entitled Apparatus And Method For Controlling Vapor Phase Within An Enclosure, U.S. Pat. No. 5,057,951 to Eckerd, entitled Breather Vent Assembly Formed In A Sealed Disk Drive Housing, U.S. Pat. No. 5,406,431 to Beecroft, entitled Filter System For Type II HDD, U.S. Pat. No. 5,012,360 to Yamauchi et al., entitled Defumidifier For Magnetic Disk Apparatus, U.S. Pat. No. 5,030,260 to Beck et al., entitled Disk Drive Breather Filter, U.S. Pat. No. 4,967,295 to Yamauchi et al., entitled Humidity Regulating Apparatus For Magnetic Disk Drive, U.S. Pat. No. 4,751,594 to Blanks, entitled Low Diffusion Disk Drive Breather Vent, U.S. Pat. No. 4,863,499 to Osendorf, entitled Anti-Diffusion Chemical Breather Assembly For Disk Drives, U.S. Pat. No. Re. 64,497, to Blanks, entitled Low Diffusion Disk Drive Breather Vent, and U.S. Pat. No. H1067 to Eckerd, entitled Breather Vent Assembly Formed In A Sealed Disk Drive Housing.